Fixed charges at the HfO2/SiO2 interface: Impact on the memory window of FeFET

Abstract

In this article, the impact of interfacial fixed charges on the memory window (MW) of HfO2-based ferroelectric field-effect transistor (FeFET) is investigated using technology computer-aided design (TCAD) device simulations. We have considered the presence of fixed charges at the interface between the ferroelectric layer (FE) and the interlayer dielectric (IL) of FeFET with metal/ferroelectric/interlayer/Si (MFIS) gate structure. Our study indicates that the presence of fixed charges affects the polarization and corresponding depolarization field in the ferroelectric. Positive and negative interface charges can align the polarization direction. The MW degradation is observed with the increase in the fixed charge concentration (Qf).

Keywords

• Ferroelectric
• FeFETs
• Memory window
• Fixed charge
• Nonvolatile memory (NVM)